I really like Ubuntu 10.10. Eminently readable and easy on the eyes. That, and it looks really modern (to me).
It took me some time to get it to work properly, though. Is the Kobo picky about how you call your fonts? I renamed them to -Bold, -Italic, -BoldItalic and -Regular and now it looks ok, but that may have been a fluke (because I did the same for Gentium and it displays Italics as Bold (ok I haven't checked if I screwed up renaming
You'd think these fonts include some information internally so that the programs don't have to rely on their names?
Can you all share whether you have had to rename your fonts, or what hoodoo you'd had to do to get your fonts to work properly?
EDIT: if someone could post a zip with the exact Gentium fonts the way they work for them (including italics), I'd be very happy. I can't get them to work properly.